Improve test suite (#628)

Signed-off-by: Thomas Miceli <tho.miceli@gmail.com>

test2.md

@@ -0,0 +1,158 @@
+---
+description: Testing handler and middleware
+slug: /testing
+sidebar_position: 13
+---
+
+# Testing
+
+## Testing Handler
+
+`GET` `/users/:id`
+
+Handler below retrieves user by id from the database. If user is not found it returns
+`404` error with a message.
+
+### CreateUser
+
+`POST` `/users`
+
+- Accepts JSON payload
+- On success `201 - Created`
+- On error `500 - Internal Server Error`
+
+### GetUser
+
+`GET` `/users/:email`
+
+- On success `200 - OK`
+- On error `404 - Not Found` if user is not found otherwise `500 - Internal Server Error`
+
+`handler.go`
+
+```go
+package handler
+
+import (
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+)
+
+type (
+	User struct {
+		Name  string `json:"name" form:"name"`
+		Email string `json:"email" form:"email"`
+	}
+	handler struct {
+		db map[string]*User
+	}
+)
+
+func (h *handler) createUser(c echo.Context) error {
+	u := new(User)
+	if err := c.Bind(u); err != nil {
+		return err
+	}
+	return c.JSON(http.StatusCreated, u)
+}
+
+func (h *handler) getUser(c echo.Context) error {
+	email := c.Param("email")
+	user := h.db[email]
+	if user == nil {
+		return echo.NewHTTPError(http.StatusNotFound, "user not found")
+	}
+	return c.JSON(http.StatusOK, user)
+}
+```
+
+`handler_test.go`
+
+```go
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/labstack/echo/v4"
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	mockDB = map[string]*User{
+		"jon@labstack.com": &User{"Jon Snow", "jon@labstack.com"},
+	}
+	userJSON = `{"name":"Jon Snow","email":"jon@labstack.com"}`
+)
+
+func TestCreateUser(t *testing.T) {
+	// Setup
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(userJSON))
+	req.Header.Set(echo.HeaderContentType, echo.MIMEApplicationJSON)
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+	h := &handler{mockDB}
+
+	// Assertions
+	if assert.NoError(t, h.createUser(c)) {
+		assert.Equal(t, http.StatusCreated, rec.Code)
+		assert.Equal(t, userJSON, rec.Body.String())
+	}
+}
+
+func TestGetUser(t *testing.T) {
+	// Setup
+	e := echo.New()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+	c.SetPath("/users/:email")
+	c.SetParamNames("email")
+	c.SetParamValues("jon@labstack.com")
+	h := &handler{mockDB}
+
+	// Assertions
+	if assert.NoError(t, h.getUser(c)) {
+		assert.Equal(t, http.StatusOK, rec.Code)
+		assert.Equal(t, userJSON, rec.Body.String())
+	}
+}
+```
+
+### Using Form Payload
+
+```go
+// import "net/url"
+f := make(url.Values)
+f.Set("name", "Jon Snow")
+f.Set("email", "jon@labstack.com")
+req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(f.Encode()))
+req.Header.Set(echo.HeaderContentType, echo.MIMEApplicationForm)
+```
+
+### Setting Path Params
+
+```go
+c.SetParamNames("id", "email")
+c.SetParamValues("1", "jon@labstack.com")
+```
+
+### Setting Query Params
+
+```go
+// import "net/url"
+q := make(url.Values)
+q.Set("email", "jon@labstack.com")
+req := httptest.NewRequest(http.MethodGet, "/?"+q.Encode(), nil)
+```
+
+## Testing Middleware
+
+*TBD*
+
+For now you can look into built-in middleware [test cases](https://github.com/labstack/echo/tree/master/middleware).